This invention relates to a directional drill and, more particularly, to a directional drill specifically adapted for railway related applications.
Directional drills are, of course, well known, principally in the oil and gas industry and for underground pipe laying applications. In such applications, the drill generally introduces the drill string to the surface of the ground at an acute angle. A directional drill bit is used at the head of the drill string. It""s location underground may be determined by a locator and its position changed so that the drill bit may be guided along a desired course underground, typically toward an area of interest which area may hold an oil or gas deposit. Other directional drills may be used for drilling a hole over a relatively small distance without a guided drill bit where any unforeseen obstacles are generally not present and the drill bit need not be guided.
All of the above-identified drills have a common characteristic, however. They may choose their location to set up and install the drilling apparatus. The location for setting up a drilling apparatus for oil and gas will be selected with care and much flexibility is present. The is drilling apparatus is not readily transportable with many hours being needed for setting up and removing the drilling apparatus. Generally, therefore, the drilling apparatuses are all located on relatively horizontal ground surfaces with ample area for installing the drilling apparatus extending around the drilling location.
In recent years, the laying of fiber optic telecommunications cable along railway right-of-way has been undertaken with success as a collaborative venture between the owners of the right-of-way, generally railways, and the owners of the fiber optic cable network. The right-of-way avoids the necessity of purchasing rights for the cable network. In return for allowing the railway area to be used for carrying the fiber optic cables, the railway generally obtains the right to carry some of its data over a line or lines. The fiber optic cable is then laid within or under the ballast of the railway. Such cable networks can be extensive, extending from coast to coast and generally following the railway lines. Such fiber optic cables may be appropriately installed in certain areas by drilling a hole into which the cable sheathing is positioned to pass an obstacle or otherwise to place the cable underground where it will not be disturbed.
The drilling apparatuses identified above, however, are not appropriate for such fiber optic cable laying activities in settings adjacent to railway track. First, the apparatuses must be portable and able to quickly move from position to position since trains may be using the track about which the drilling activity is being conducted. Second, the apparatuses must be transportable along the railway track itself since the only efficient way to move the apparatuses may be by the rails. Third, since the ballast beneath the rails may be configured with a slope downwardly from the track, previous apparatuses are unable to work on such slopes in a configuration in which the drill itself is generally horizontal which is necessary for the drilling operation itself.
According to one aspect of the invention, there is provided a directional drill for drilling a hole beneath a ground surface, said drill comprising a drill head mounted to apply rotary motion to drill pipe and longitudinal pressure on one end of said drill pipe during the drilling operation, said drill head applying rotary motion to said drill pipe and longitudinal pressure on one end of said drill pipe when said pipe is withdrawn from said drill hole, said drill head moving from a first position on a rack wherein said drill pipe first enters said hole being drilled to a second position on said rack when said pipe is further within said hole being drilled, said directional drill having a frame and a set of tires mounted on a subframe, said frame being rotatable relative to said subframe o over a predetermined angle and about a longitudinal axis of said drilling apparatus.